It is known to provide a portable light tower for emitting light along with an attached light diffuser. A portable light tower generally has a light emitter positioned in the upper end of an extendable and retractable supporting column vertically mounted on a power generator. The apparatus as a whole is commonly called a portable light tower. Additionally, diffusers for light emitters are also known. For example U.S. Pat. Nos. 6,305,827, 7,264,382, and 7,246,913 embody light diffusers that diffuse light from a portable light tower or portable lamp.
Portable light towers are available in a variety of sizes and emit a variety of light powers, depending on the operator's selection of a light tower as well as the operator's bulb selection for varying uses. In one species of portable light tower, the emitted light radiated from the lighting instrument is bright enough to allow a worker at a work site to easily perform work at night. However, although the lights provide sufficient light to work under, these lights are typically very bright and create problems when workers or others look up into the lights. This can be very hazardous to workers who are, for example but not limited to, operating a vehicle or working on scaffolding. When the workers look up into the bright light there exists a possibility that they can be temporarily blinded, crash a vehicle, or perform an action that leads to injury. Additionally, bright light towers can be a hazard to the public as well. For example, night working road construction crews often use light towers to illuminate their work areas. A motorist passing by the bright light of the light tower may be temporarily blinded or become fixated on the bright lights and fail to pay attention to the road or not be able to see the road. This creates a significant safety hazard to the motorist, the road construction crew, and any other person or object on the road.
Another problem with the bright, undiffused lights is that they create shadows on the work area. As workers are often required to work in a variety of positions, often times with their backs to the light tower, they create a variety of shadows that can severely inhibit their work productivity and lead to serious safety concerns. For example, a worker faces a difficult situation when he needs to perform a task but his only possible body position would be facing away from the light tower. Consequently, his body casts a dark shadow over the area where he is working and he runs a much higher risk of injury as he cannot adequately view the work area.
Glare can also present a problem in work environments. The bright light emitted by the light tower can glare off of reflective surfaces and interfere with work operations. An example is when glare from the light of a light tower is picked up by a camera and interferes with the scene recorded by the camera. Another situation that requires decreased glare is when a construction crew is working on a road at night.
A further problem is that as light towers are often very bright for illuminating large areas, large bulbs are used that can create copious amounts of heat. As current light diffusers do not use sufficient ventilation to allow air circulation, heat builds up in the light diffusers and can cause damage to the electrical equipment of the light tower or even cause the light diffuser to ignite. Additionally, this can make the equipment very difficult to maintain, to repair, or even to replace malfunctioning lights unless the tower is turned off and allowed to cool. In each of the situations work efficiency is significantly decreased as the full capabilities of the light tower are not utilized.
Another problem facing portable light towers and light diffusers is that often times the light diffuser does not have sufficient structure in order to prevent the light diffuser from coming into contact with the light. This can lead to a fire as the lights can be very hot and can ignite the light diffusing material of the light diffuser. Additionally, without an adequate underlying structure the light diffuser is expanded as long as air is forced into, or sealed within the diffuser envelope. If the light diffuser deflates, it can also come into contact with the often hot lights and ignite, or burn the diffuser material. Several attempts have been made to solve this problem. However, these attempts have not solved the problem as they still often use an air system with forced air to maintain an inflated balloon or an envelope that still uses a forced or sealed air supply to stay inflated. This requires an air pump or fan positioned to push air into the diffuser. Consequently, this requires an additional expenditure of energy to run the pump or fan making the light tower less efficient to operate.
In addition to the previous difficulties, current light towers also are not easily transportable when they are attached to a light diffuser or even when not attached to a light diffuser. In order to transport current light diffusers, they typically must be entirely removed from the light tower. When the light diffusers are removed from the light towers they are often very large and bulky making them awkward to transport alone as well as when attached to a light tower. Additionally, it is very difficult to remove the light diffusers from the light towers without completely disassembling the light tower diffuser. This leads to an increased amount of time spent assembling and disassembling the light diffusers. Consequently, the overall efficiency of the worksite decreases as it takes workers more time to assemble and disassemble the diffuser while other workers may have to wait additional time until they have adequate light in which to work.
The current state of light diffusers for portable light towers prevents the light diffuser and light tower from being easily transported. Light towers are typically transported by retracting the telescoping pole and folding the pole forward towards the tongue of the trailer. When a large light diffuser is left fully assembled to the telescoping tower, it is very difficult to transport because the light diffuser is very bulky. Furthermore, when the light diffuser is fully assembled on the light tower while in transit, the light diffuser presents a significant amount of wind resistance as it is big and bulky. In this situation, the light diffuser is much more prone to damage from flying debris, inclement weather, and acts of vandalism if it is left fully attached to the portable light tower while in transit.
For example, U.S. Pat. No. 7,264,382 to Yoshimori et al., to a light diffuser, provides a light emitting apparatus supported by a rigid, extendable frame. The rigid frame provides a support system with upward running extendable bars that support the light emitter as well as an air intake which provides suction to intake air in order to keep a balloon or envelope for diffusing light fully inflated. The balloon or envelope is attached via an attachment to the light supporting frame at the top and bottom of the frame. The apparatus apparently does not include a complete frame for supporting the balloon or envelope, rather it apparently provides a rigid frame for supporting a light emitter and the balloon attaches at the top and at the bottom of the frame. Accordingly, the rigid frame is not flexible nor does it appear to provide a support structure for the balloon or envelope which is likely supported by air sucked in through the intake. Additionally, the frame apparently does not provide a means for quickly closing or opening the light diffuser.
Another patent to a light diffuser, U.S. Pat. No. 7,246,913 to Ossolinski, apparently discloses a lighting apparatus with a frame and an envelope that is formed from two sheets of acrylic formed into dome shapes in order to slow deflation rate. Although the diffuser on this light tower apparently does not require an air supply, it apparently does establish that a preferred method to operate the light diffuser may be with an air supply being pumped into or sucked into the diffuser balloon. As the balloon likely relies on an air supply creating pressure within the balloon to remain inflated, it may not provide sufficient openings in order to allow air circulation for cooling the lights. Additionally, these balloons appear to require a near constant air flow into the balloon to remain inflated. This likely requires a near constantly operating air pump. In addition to the aforementioned problems, it appears that of the diffusers known in the art apparently no diffuser presents an easily disassembled or easily deployed light diffuser.
Accordingly an object of the invention is to provide a system for quickly disassembling the light diffuser for storage or periods of non use and quickly deploying the system for operation.
Accordingly, a further object of the present invention is to provide a circulation opening on the top of the light diffuser and an opening on the bottom of the light diffuser for increased air circulation.
A third object of the invention is to provide a system for easily disassembling and strapping down the light diffuser for transport of the portable light tower.
A fourth object of the invention is to provide a diffuser on a light tower that does not create a significant amount of glare, shadows, or temporary blindness if someone looks into the light.
A fifth object of the invention is to provide a diffuser that is for use with any manufacturer's light tower.